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Distinguish the types of environmental hazardous gases

1. Determine the presence of environmental hazardous gases

CLASSⅠ(Flammable Gases, Vapors or Liquids)

Area Classification

Division 1:

Where ignitable concentrations of flammable gases, vapors or liquids can exist all of the time or some of the time under normal operating conditions.

Division 2:

Where ignitable concentrations of flammable gases, vapors or liquids are not likely to exist under normal operating conditions.

Zone 0:

where ignitable concentrations of flammable gases, vapors or liquids are present continuously or for long periods of time under normal operating conditions.

Zone 1:

Where ignitable concentrations of flammable gases, vapors or liquids are likely to exist under normal operating conditions.

Zone2:

where ignitable concentrations of flammable gases, vapors or liquids are not likely to exist under normal operation conditions.

2. Distinguish the types of environmental hazardous gases

Groups

Division 1 and 2 Zone 0, 1 and 2

A(acetylene) IIC (acetylene & hydrogen)

B (hydrogen) IIC (acetylene & hydrogen)

C (ethylene) IIB (ethylene)

D (propane) IIA (propane)

3. Telephone max. surface temperature(less than gas ignition temperature)

Temperature classes

Division 1 and 2: Zone 0, 1 and 2:

T1 (≤450°C) T1 (≤450°C)

T2 (≤300°C) T2 (≤300°C)

T2A (≤280°C) -

T2B (≤260°C) -

T2C (≤230°C) -

T2D (≤215°C) -

T3 (≤200°C) T3 (≤200°C)

T3A (≤180°C) -

T3B (≤165°C) -

T3C (≤160°C) -

T4 (≤135°C) T4 (≤135°C)

T4A (≤120°C) -

T5 (≤100°C) T5 (≤100°C)

T6 (≤85°C) T6 (≤85°C)

4. Equipment protection methods and corresponding marks

4.1 International Protection Techniques (Equipment Protection Levels) 4.2 North American Protection Techniques

Zone0:

• Intrinsic safety,"ia"(Ga)

• Encapsulation,"ma"(Ga) or

"m" for CAN

• Class I,Div 1 intrinsic safety

Div.1:

• Intrinsic safety

• Explosionproof

• Purged/pressurized (Type X or Y)

• Any Class I, Zone 0 technique

Zone1:

• Flameproof,"d"(Gb)

• Pressurization,"px" or "py"(Gb)

or "p" fo4 CAN

• Powder filling,"q" (Gb)

• Oil immersion,"o" (Gb)

• Increased safety,"e"(Gb)

• Intrinsic safety,"ib"(Gb)

• Encapsulation, "mb" (Gb) or

"m" for CAN

• Any Zone 0 technique

• Any Class I, Div 1 technique

Div.2:

• Hermetically-sealed

• Non-incendive

• Non-sparking

• Purged / pressurized (Type Z)

• Sealed

• Any Class I, Division 1 technique

• Any Class I, Zone 0,1 or 2 technique

Zone2:

• Pressurization,"pz"(Gc) or

"n" for CAN

• Intrinsic safety,"ic"(Gc) or

"n" for CAN

• Encapsulated,"nC"(Gc)

• Enclosed-break,"nC"(Gc)

• Energy-limited,"nL"(Gc)

• Hermetically-sealed,"nC"(Gc)

• Non-incendive,"nC"(Gc)

• Non-sparking,"nA"(Gc)

• Restricted breathing,"nR"(Gc)

• Sealed,"nC"(Gc)

• Encapsulation,"mc"(Gc) or

"n" for CAN

• Any Zone 0 or 1 technique

• Any Class 1, Div 1 or 2 technique

5. Determine the presence of dust

CLASⅡ(Combustible Dusts)

Area Classification

Division1:

Where ignitable concentrations of combustible dust can exist all of the time or some of the time under normal operating conditions.

Division 2:

Where ignitable concentrations of combustible dust are not likely to exist under normal operating conditions.

Zone 20:

Where ignitable concentrations of combustible dust or ignitable fibers/flyings are present continuously or for long periods of time under normal operating conditions.

Zone 21:

Where ignitable concentrations of combustible dust or ignitable fibers/flyings are likely to exist under normal operating conditions.

Zone 22:

Where ignitable concentrations of combustible dust or ignitable fibers/flyings are not likely to exist under normal operating conditions.

6. Distinguish the type of dust

Groups

Division 1 and 2: Zone 20, 21 and 22:

E (metal dust - Div. 1 only) IIIC (conductive dust)

F (carbonaceous dust) IIIB (non-conductive dust)

G (non-conductive dust) IIIB (non-conductive dust)

- IIA (combustible flyings)

7. Telephone Max. Surface Temperature

Temperature Classes

Division 1 and 2: Zone 20, 21 and 22:

T1 (≤ 450°C) None.

T2 (≤ 300°C) ----------------------------

T2A (≤ 280°C) Note: For Zone 20, 21

T2B (≤ 260°C) and 22, equipment

T2C (≤ 230°C) shall be marked to

T2D (≤ 215°C) show the operating

T3 (≤ 200°C) temperature

T3A (≤ 180°C) (maximum surface

T3B (≤ 165°C) temperature)

T3C (≤ 160°C)

T4 (≤ 135°C)

T4A (≤ 120°C)

T5 (≤ 100°C)

T6 (≤ 85°C)

8. Equipment protection methods and corresponding marks

8.1 International Protection Techniques (Equipment Protection Levels)

Zone 20:

• Enclosure, "ta" (Da)

• Intrinsic safety, "ia" (Da)

• Encapsulation, "ma" (Da)

• Any Class II, Div 1 technique

8.2 North American Protection Techniques

Div.1

• Intrinsic safety

• Dust-ignitionproof

• Pressurized

• Any Zone 20 technique

Zone21:

• Enclosure, "tb" (Db) or "t" for USA

• Pressurization, "p" (Db)

• Intrinsic safety, "ib" (Db)

• Encapsulation, "mb" (Db)

• Any Zone 20 technique

• Any Class II, Div 1 technique

Div.2

• Dust-tight

• Hermetically-sealed

• Non-incendive

• Pressurized

• Sealed

• Any Class II, Division 1 technique

• Any Zone 20, 21 or 22 technique

Zone 22:

• Enclosure, "tc" (Dc)

• Pressurization, "p" (Dc)

• Intrinsic safety, "ic" (Dc)

• Encapsulation, "mc" (Dc)

• Any Zone 20 or 21 technique

• Any Class II, Div 1 or 2 technique

Explosion-proof area classification reference

FOR EXAMPLE( Explosion poof telephone certification standard)

II 2G Ex eb ib [ib Gb] mb IIC T6 Gb

II 2D Ex ib [ib Db] tb IIIC T80 °C Db IP66

II: for surface industry

2: Permitted in Zone 1 and Zone 21

G: gas

D: dust

Ex: Denotes explosion protection

eb: Increased safety

tb: Enclosure protection

ib Gb: Intrinsic safety

ib Db: Intrinsic safety

mb: Encapsulation

ib: Intrinsic safety

IIC: acetylene & hydrogen

IIIC: conductive dust

T6: equipment surface temperature ≤85°C

IP66: ingress protection standard